Increasing innovation in rapid prototyping (RP) and additive manufacturing (AM), also known as 3D printing, is bringing about major changes in translational surgical research.

This review describes the current position in the use of additive manufacturing in orthopaedic surgery.

Cite this article: Bone Joint J 2018;100-B:455-60.

Background

A dedicated referral pathway for patients with bony metastases was introduced at Guy's and St Thomas’ Hospitals (GSTT) in 2009. The aim was to facilitate prompt, consultant-led decision-making and intervention for patients at risk of pathological fracture of long bones.

Aims

To determine whether there is any benefit using a minimally invasive trans-sartorial approach as described by Professor Søballe compared to the ilio-femoral for peri-acetabular osteotomy

Background: Osteoarthritis of the first trapeziometacarpal (TMC) joint is a disabling disease which reduces the function of the thumb and the hand. Replacement arthroplasty offers good range of joint motion and also maintains thumb length thus improving tip pinch grip.

Aims: This study reviews the results of TMCJ arthroplasty using a cemented metal-on-polyethylene implant (Sr TMC, Avanta^®).

Methods and Results: Between 2001–2005 seventy two (n = 72) TMCJ cemented Arthroplasties were performed by a single surgeon. Patients were followed in the clinics for up to seven years (median follow up 36 months, range 24–84). Patients were reviewed clinically and radiologically by two independent assessors. For outcome, Sollerman and Quick-DASH (Disabilies of the Arm, Shoulder and Hand Score) scores were used. A Jamar dynamometer was used to assess the grip and pinch strengths. Thirty six patients (46 joints, n = 46), were seen at final follow up. There were 13 male and 23 female patients. Ten patients had bilateral TMCJ replaced.

Six patients were revised to trapeziectomy and ligament reconstruction with tendon interposition. Four for aseptic loosening and two for dislocation. With revision as end point the survival rate at median follow up of 36 months was 89%. At final follow up mean Quick DASH score was 29.2 and mean Sollerman Score was 77.1. Radiological review of the surviving joints showed subsidence of trapezial component in 4 joints. However these patients had good hand function and grip strength and therefore declined revision surgery. We found that the radiological findings did not correlate with clinical findings. 83% patients were satisfied with the outcome of their treatment.

Conclusion: Early results of Sr-TMC (Avanta) joint replacement are encouraging. We recommend the use of this prosthesis for osteoarthritis of the trapeziometacarpal joint.

Human recombinant Osteogenic Protein 1 or rhBMP-7 is licensed for use in tibial non-union where autologous bone grafting has failed. Through its osteoconductive and osteoinductive properties, its application may be more widely applied. We audited our use of rhBMP-7 and present the largest series currently reported in the literature.

We reviewed 107 consecutive patients on whom rhBMP-7 was used over a 5-year period (2002–2007). Demographic and clinical details (e.g indication, site, use of adjuncts, previous surgery, smoking status, time to union, mean follow up etc) were entered into an electronic spreadsheet.

RhBMP-7 was used in 112 sites on 107 patients (65 male, 42 female). Ages ranged from 16yrs to 89yrs (mean 47.6). Non-union was the main indication for surgery (82 cases). RhBMP-7 was used alone in 39 cases and with autologous bone graft (56 cases). In other cases demineralised bone matrix, USS and bone allograft were used as adjuncts. Tibia (42 cases), femur (29 cases), humerus (21 cases) were the most common sites of administration. Mean number of operations prior to use of rhBMP-7 was 1.6 (range 1–20). In all cases, union was achieved in 65% (73/112) with a mean union time 5.8 months. The ‘rhBMP-7 alone’ subgroup demonstrated union in 83% (30/36), mean union time 5.15 months. 68% (56/82) of cases treated for nonunion subsequently united with rhBMP-7.

Our results suggest rhBMP-7 is useful in the management of fracture non-union and limb reconstruction surgery irrespective of site. It promotes bone healing of non-unions subjected to multiple operations previously. It may be indicated in those patients in whom autologous bone graft harvest is undesirable or not possible or as an adjunct to bone grafting. Moreover we did not detect any adverse reactions specific to the administration of rhBMP-7.

The aim of this prospective study was to report the mid-term results of arthroscopic repair of full thickness rotator cuff tears. Arthroscopic cuff repair, under regional interscalene block and balanced anaesthesia, was performed in 104 shoulders (102 patients). There were 52 female and 50 male patients with a mean age of 64 years (range 41 to 79). The mean size of the cuff tear was 3cm (range 1cm to 6 cm). Patients were discharged within 24 hours and followed a specific rehabilitation protocol. An assessment was performed pre-operatively and at a mean follow-up of 7 months (range 3 to 24 months). Outcome measures included pain, activities of daily living, shoulder function and level of patient satisfaction. Satisfactory pain relief was achieved in 98 patients (94%) with significant pain relief in 87 patients (83.6 %) and good in 12 patients (11.5 %). Ninety -six patients (92.3%) reported a satisfactory improvement in activities of daily living, with significant improvement in 89 (85.6%) and good in seven (6.7%). High levels of patient satisfaction were noted in 93 patients. Seven patients were moderately satisfied and two patients were not satisfied. The mean shoulder score improved from 29 pre-op to 82 post-op, and the shoulder function score from 32 pre-op to 84 post-op. No difference in outcome was found when the subgroup of 65 patients over the age of sixty was compared to the group of 37 patients under the age of sixty. We believe that this study has shown that the arthroscopic repair of the rotator cuff can consistently achieve a satisfactory outcome. It may therefore be considered as an alternative to the traditional open techniques.

The aim of this prospective study was to report the mid-term results of arthroscopic repair of full thickness rotator cuff tears.

One hundred and four shoulders in 102 consecutive patients were operated within a two-year period. There were 52 female and 50 male patients with a mean age of 64 years (range 41 to 79). Standard arthroscopic techniques of cuff repair were used, under regional inter-scalene block and balanced anaesthesia. The mean size of the cuff tear was 3 cm (range 1 to 6 cm). Patients were discharged within 24 hours and followed a specific rehabilitation protocol. An assessment was performed pre-operatively and at a mean follow-up of 7 months (range 3 to 24 months). Outcome measures included pain, activities of daily living, shoulder power and function and level of patient satisfaction.

Satisfactory pain relief was achieved in 98 patients (94%) with significant pain relief in 87 patients (83.6 %) and good in 12 patients (11.5 %). Ninety -six patients (92.3%) reported a satisfactory improvement in activities of daily living, with significant improvement in 89 (85.6%) and good in 7 (6.7%). Shoulder power was markedly improved in 95 patients (93%). High levels of patient satisfaction were noted in 93 patients. Seven patients were moderately satisfied and two patients were not satisfied.

The mean shoulder score improved from 29 pre-op to 82 post-op, and the shoulder function score from 32 pre-op to 84 post–op. Similar results were found when the subgroup of 65 patients over the age of sixty was compared to the group of 37 patients under the age of sixty. No difference in outcome was also noted in relation to the size of the tear, length of follow –up or sex of the patient.

We believe that this study has shown that the arthroscopic repair of the rotator cuff can consistently achieve a satisfactory outcome. It may therefore be considered as an alternative to the traditional open techniques.

We present a new CT-based method which measures cover of the femoral head in both normal and dysplastic hips and allows assessment of acetabular inclination and anteversion. A clear topographical image of the head with its covered area is generated.

We studied 36 normal and 39 dysplastic hips. In the normal hips the mean cover was 73% (66% to 81%), whereas in the dysplastic group it was 51% (38% to 64%). The significant advantage of this technique is that it allows the measurements to be standardised with reference to a specific anatomical plane. When this is applied to assessing cover in surgery for dysplasia of the hip it gives a clearer understanding of where the corrected hip stands in relation to normal and allows accurate assessment of inclination and anteversion.

Introduction: Assessing coverage of the femoral head is a crucial element in acetabular surgery for hip dysplasia. Radiographic indices give rather limited information. We present a novel ct-based method that gives an image of the head with the covered area precisely represented. We used this method to measure femoral head coverage in a series of normal hips and in a prospective study of patients with hip dysplasia undergoing peri-acetabular osteotomy.

Methods: Thirteen normal and ten dysplastic hips were studied. On each CT scan anatomical landmarks were assigned on the 3d reconstructed image and used to define the frame of reference. Points were assigned on the femoral head surface and the superior half of the acetabular rim after aligning the pelvis in the anterior pelvic plane. An image was produced representing the femoral head and its covered part. The fraction of the head that was covered was calculated.

Results: The average femoral head coverage in the normal hips was 73.9% (sd 3.2). The average coverage in the dysplastic group was 50.7% (sd 7.9) and after undergoing peri-acetabular osteotomy the average was 67% (sd 6.2).

Conclusion: This is the first study to our knowledge that has used a reliable measurement technique to give an indication of the percent coverage of the femoral head by the acetabulum in the “normal hip”. When this is applied to assessing coverage in surgery to address hip dysplasia it gives a clearer understanding of where the corrected hip stands in relation to a normal hip, and this should allow for better determination of the likely outcome of this type of surgery.